rename deferredShadow => screenspaceshadow + change to RG16

com.unity.render-pipelines.high-definition/CHANGELOG.md

 
 ### Changed
 - Shader code refactor: Split MaterialUtilities file in two parts BuiltinUtilities (independent of FragInputs) and MaterialUtilities (Dependent of FragInputs)
+- Change screen space shadow rendertarget format from ARGB32 to RG16
 
 ## [3.1.0-preview]
 

com.unity.render-pipelines.high-definition/HDRP/Debug/DebugDisplay.cs

         // Lighting
         MinLightingFullScreenDebug,
         SSAO,
-        DeferredShadows,
+        ScreenSpaceShadows,
         PreRefractionColorPyramid,
         DepthPyramid,
         FinalColorPyramid,

com.unity.render-pipelines.high-definition/HDRP/Lighting/LightLoop/LightLoop.cs

             public bool outputSplitLighting;
         }
 
-        public void RenderDeferredDirectionalShadow(HDCamera hdCamera, RTHandleSystem.RTHandle deferredShadowRT, RenderTargetIdentifier depthTexture, CommandBuffer cmd)
+        public void RenderScreenSpaceShadows(HDCamera hdCamera, RTHandleSystem.RTHandle deferredShadowRT, RenderTargetIdentifier depthTexture, CommandBuffer cmd)
         {
             bool sunLightShadow = m_CurrentSunLight != null && m_CurrentSunLight.GetComponent<AdditionalShadowData>() != null && m_CurrentSunLightShadowIndex >= 0;
 
                 return;
             }
 
-            using (new ProfilingSample(cmd, "Deferred Directional Shadow", CustomSamplerId.TPDeferredDirectionalShadow.GetSampler()))
+            using (new ProfilingSample(cmd, "Deferred Directional Shadow", CustomSamplerId.TPScreenSpaceShadows.GetSampler()))
             {
                 Vector4         lightDirection = Vector4.zero;
                 Vector4         lightPosition = Vector4.zero;
-                //  - if there is a sun light casting shadow, we need to use comput directional light shadows
+                //  - if there is a sun light casting shadow, we need to use compute directional light shadows
                 //    and contact shadows of the dominant light (or the directional if contact shadows are enabled on it)
                 //  - if there is no sun or it's not casting shadows, we don't need to compute it's costy directional
                 //    shadows so we only compute contact shadows for the dominant light

com.unity.render-pipelines.high-definition/HDRP/Lighting/ScreenSpaceShadow.compute

     contactShadow = ComputeContactShadow(posInput, direction);
 #endif
 
-    _DeferredShadowTextureUAV[pixelCoord] = float4(shadow, contactShadow, 1.0, 1.0);
+    _DeferredShadowTextureUAV[pixelCoord] = float4(shadow, contactShadow, 1.0, 1.0); // Note: RT is RG16 format
 }
 
 [numthreads(DEFERRED_SHADOW_TILE_SIZE, DEFERRED_SHADOW_TILE_SIZE, 1)]
 
     contactShadow = ComputeContactShadow(posInput, direction);
 
-    _DeferredShadowTextureUAV[pixelCoord] = float4(1.0, contactShadow, 1.0, 1.0);
+    _DeferredShadowTextureUAV[pixelCoord] = float4(1.0, contactShadow, 1.0, 1.0); // Note: RT is RG16 format
 }

com.unity.render-pipelines.high-definition/HDRP/RenderPipeline/HDCustomSamplerId.cs

         Forward,
         RenderSSAO,
         RenderShadows,
-        RenderDeferredDirectionalShadow,
+        ScreenSpaceShadows,
         BuildLightList,
         BlitToFinalRT,
         Distortion,
         TPPrepareLightsForGPU,
         TPPushGlobalParameters,
         TPTiledLightingDebug,
-        TPDeferredDirectionalShadow,
+        TPScreenSpaceShadows,
         TPTileSettingsEnableTileAndCluster,
         TPForwardPass,
         TPForwardTiledClusterpass,

com.unity.render-pipelines.high-definition/HDRP/RenderPipeline/HDRenderPipeline.cs

         RTHandleSystem.RTHandle m_CameraStencilBufferCopy;
 
         RTHandleSystem.RTHandle m_VelocityBuffer;
-        RTHandleSystem.RTHandle m_DeferredShadowBuffer;
+        RTHandleSystem.RTHandle m_ScreenSpaceShadowsBuffer;
         RTHandleSystem.RTHandle m_AmbientOcclusionBuffer;
         RTHandleSystem.RTHandle m_DistortionBuffer;
 
 
             m_DistortionBuffer = RTHandles.Alloc(Vector2.one, filterMode: FilterMode.Point, colorFormat: Builtin.GetDistortionBufferFormat(), sRGB: Builtin.GetDistortionBufferSRGBFlag(), name: "Distortion");
 
-            // TODO: For MSAA, we'll need to add a Draw path in order to support MSAA properly
-            m_DeferredShadowBuffer = RTHandles.Alloc(Vector2.one, filterMode: FilterMode.Point, colorFormat: RenderTextureFormat.ARGB32, sRGB: false, enableRandomWrite: true, name: "DeferredShadow");
+            // TODO: For MSAA, we'll need to add a Draw path in order to support MSAA properlye
+            // Use RG16 as we only have one deferred directional and one screen space shadow light currently
+            m_ScreenSpaceShadowsBuffer = RTHandles.Alloc(Vector2.one, filterMode: FilterMode.Point, colorFormat: RenderTextureFormat.RG16, sRGB: false, enableRandomWrite: true, name: "ScreenSpaceShadowsBuffer");
 
             if (Debug.isDebugBuild)
             {
             RTHandles.Release(m_AmbientOcclusionBuffer);
             RTHandles.Release(m_VelocityBuffer);
             RTHandles.Release(m_DistortionBuffer);
-            RTHandles.Release(m_DeferredShadowBuffer);
+            RTHandles.Release(m_ScreenSpaceShadowsBuffer);
 
             RTHandles.Release(m_DebugColorPickerBuffer);
             RTHandles.Release(m_DebugFullScreenTempBuffer);
                                 hdCamera.SetupGlobalStereoParams(cmd);
                         }
 
-                        using (new ProfilingSample(cmd, "Deferred directional shadows", CustomSamplerId.RenderDeferredDirectionalShadow.GetSampler()))
+                        using (new ProfilingSample(cmd, "Screen space shadows", CustomSamplerId.ScreenSpaceShadows.GetSampler()))
-                            if (m_CurrentDebugDisplaySettings.fullScreenDebugMode == FullScreenDebugMode.DeferredShadows)
+                            if (m_CurrentDebugDisplaySettings.fullScreenDebugMode == FullScreenDebugMode.ScreenSpaceShadows)
-                                HDUtils.SetRenderTarget(cmd, hdCamera, m_DeferredShadowBuffer, ClearFlag.Color, CoreUtils.clearColorAllBlack);
+                                HDUtils.SetRenderTarget(cmd, hdCamera, m_ScreenSpaceShadowsBuffer, ClearFlag.Color, CoreUtils.clearColorAllBlack);
-                            m_LightLoop.RenderDeferredDirectionalShadow(hdCamera, m_DeferredShadowBuffer, GetDepthTexture(), cmd);
-                            PushFullScreenDebugTexture(hdCamera, cmd, m_DeferredShadowBuffer, FullScreenDebugMode.DeferredShadows);
+                            m_LightLoop.RenderScreenSpaceShadows(hdCamera, m_ScreenSpaceShadowsBuffer, GetDepthTexture(), cmd);
+                            PushFullScreenDebugTexture(hdCamera, cmd, m_ScreenSpaceShadowsBuffer, FullScreenDebugMode.ScreenSpaceShadows);
                         }
 
                         if (hdCamera.frameSettings.enableAsyncCompute)